Rendering and all that nonsense..

I'm trying to batch render a scene. It's not complex as such, it's 300 frames of a simple camera animation. My scene does include some PaintFX trees and grass, but other than that it's just simple polygons with materials applied. I'm on the late 2014 5K iMac, i5 with 32gb RAM. It's rendering a total of about 30 frames a day, in 1080p.. I'm not entirely sure that it should be taking that long with the amount of RAM I'm using. I know about adjusting certain settings in the batch render options.. But I'm struggling to actually work out exactly what I should be using, and how to check it's working. I don't know whether there's some sort of hidden setting in preferences that is making it so slow, maybe my model is too large? I really don't know, there are many many questions I have but I just can't seem to find answers for them all. I just need somebody to tell me short and sweet the best tips and tricks to get the most out of my computer. If you need me to attach a picture of my scene I can! Somebody please help me.